Demographic, life-style and physiological determinants of serum per- and polyfluoroalkyl substance (PFAS) concentrations in a national cross-sectional survey of Swedish adolescents.

PER: and polyfluoroalkyl substances (PFAS) may affect adolescent health, yet factors related to PFAS concentrations in serum are poorly understood. We studied demographic, life-style and physiological determinants of serum PFAS concentrations in Swedish adolescents from a nation-wide survey, Riksmaten Adolescents 2016-17 (RMA, age 10-21 years, n = 1098). Serum samples were analyzed for 42 PFAS, using liquid chromatography-tandem mass spectrometry. The cumulative probability model was used to estimate associations between serum PFAS and determinants, using ordinal logistic regression. Legacy linear (lin-) perfluorooctanoic acid (PFOA), perfluorononaoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), lin-perfluorohexanesulfonic acid (PFHxS) and lin-/branched (br-) perfluorooctanesulfonic acid (PFOS) were quantifiable in ≥70% of the samples. The emerging PFAS 9-chlorohexanedecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS) was quantified in 5.4% of the samples, suggesting initiation of long-range transport far from production sites. Median concentrations of all legacy PFAS were <2 ng/g serum, with a few participants having very high (>100 ng/g serum) lin-PFHxS and lin-/br-PFOS concentrations due to previous high exposure from PFAS-contaminated drinking water. Legacy PFAS exposure was strongly associated with birth country of the participants and their mothers. 2-fold higher estimated adjusted mean (EAM) concentrations were seen among high income country participants with mothers from high income countries than among low/lower-middle income country participants with mothers from the same category. Menstruating females had lower br-PFOS EAM concentrations than those who were not. Iron status (plasma ferritin) among females may be a marker of intensity of menstrual bleeding, but it was not significantly associated with legacy PFAS concentrations among females. Further studies are needed to determine how physiological changes occurring around menstruation affect the toxicokinetics of PFAS in females. In conclusion, PFAS are pollutants of the industrialized world and some of the identified determinants may be overlooked confounders/effect modifiers that should be included in future PFAS/health studies among adolescents.

Healthy eating index and diet diversity score as determinants of serum perfluoroalkyl acid (PFAA) concentrations in a national survey of Swedish adolescents.

Food is an important source of perfluoroalkyl acid (PFAA) exposure for the general adult population, but few data exist for adolescents. Healthy food habits established during adolescence may positively influence health later in life. Associations between serum PFAA concentrations and a healthy eating index (SHEIA15), as well as a diet diversity score (RADDS), were determined in a nationally representative adolescent population from Sweden (Riksmaten Adolescents 2016-2017, RMA). Using consumption data from food registrations and frequency questionnaires, we additionally analyzed associations with commonly consumed food groups. Associations were analyzed by fitting a cumulative probability model using ordinal regression. Among the seven PFAAs detected in ≥70% of the 1098 participants (age 10-21 years), median concentrations ranged from <1 ng/g serum of perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perflurorundecanoic acid (PFUnDA), linear (lin-) perfluorohexanesulfonic acid (PFHxS) and branched (br-) perfluorooctanesulfonic acid (PFOS) to 1-2 ng/g serum of lin-perfluorooctanoic acid (PFOA) and lin-PFOS. PFNA, PFDA, PFUnDA and lin-PFOS concentrations were positively associated with both SHEIA15 and RADDS, a finding most likely driven by higher consumption of seafood. PFDA, PFUnDA and lin-PFOS concentrations were positively related to commonly consumed fish/shellfish groups, such as lean marine fish and shellfish. Inverse associations between PFAA concentrations and dairy consumption suggest an underlying factor behind dairy consumption that similarly affects adolescent exposure to the different PFAAs. Isomeric differences in dietary exposure between lin-PFOS and br-PFOS were suggested, as br-PFOS concentrations, in contrast to lin-PFOS, were not associated with SHEIA15, RADDS and consumption of different food groups. We conclude that Swedish adolescents, adhering to a diverse and healthy diet, appears to be more highly exposed to legacy PFAAs than those eating less healthy. Additional research is necessary for a better understanding of the health implications of healthy eating from a PFAA exposure perspective.

Vitamin D status and associations with diet, objectively measured physical activity patterns and background characteristics among adolescents in a representative national cross-sectional survey.

OBJECTIVE: To report on vitamin D status, measured as plasma 25-hydroxyvitamin D concentration (25(OH)D), the prevalence of vitamin D insufficiency and deficiency, and to explore associations between vitamin D status and background characteristics. DESIGN: Data were collected in a National Dietary Survey, Riksmaten adolescents 2016-2017. The participants completed dietary assessments and questionnaires on the web and wore accelerometers. (25(OH)D) was measured with a MS method. SETTING: Representative survey conducted in schools throughout Sweden. PARTICIPANTS: Participants attended school years 5 (Y5, mean age 12. 5 years), 8 (Y8, mean age 14. 5 years) and 11 (Y11, mean age 18 years), and included 1100 participants. RESULTS: Overall, there was no difference in plasma 25(OH)D between girls and boys. Vitamin D insufficiency differed between the three school years. The prevalence of insufficiency in Y5 was 32 (boys) and 48 (girls) percent, while in Y11 62 (boys) and 43 (girls) percent. The prevalence of deficiency in Y11 was 16 and 15 % in boys and girls, respectively. Being born outside of Sweden was associated with a 10-fold increased risk of being vitamin D deficient. Deficiency was also associated with longer time spent in sedentary intensity, a lower consumption of fortified dairy products and fats and oils. CONCLUSIONS: Vitamin D deficiency was most common in the oldest age group and being born outside of Sweden increased the risk of being deficient. The present study will form a baseline for future follow-up studies of the implementation of a new mandatory vitamin D fortification policy in 2018.

Leisure-time organised physical activity and dietary intake among Swedish adolescents.

This study aimed to investigate associations between participation in leisure-time organised physical activity (LTOPA) and dietary intake in a large representative sample of Swedish adolescents participating in the national dietary survey Riksmaten Adolescents 2016-2017. A sample of 2807 participants aged 11-12, 14-15 and 17-18 years were included. Information about LTOPA and dietary intake were collected through questionnaires and two 24-hour recalls on the web (RiksmatenFlex). For dietary intake, overall healthy eating index, intake of fruit, vegetables, candy, sugar-sweetened beverages, and the proportion of added sugar to total energy intake were analysed. Significance-testing for associations was performed with analysis of covariance. LTOPA was associated with lower sugar-sweetened beverages intake among adolescent boys (p < 0.001, ηp2 = 0.012) and girls (p = 0.007, ηp2 = 0.005), higher fruit intake among boys (p = 0.043, ηp2 = 0.003), and lower vegetable intake among girls (p < 0.001, ηp2 = 0.009). However, LTOPA was unrelated to the overall healthy eating index, candy intake, and the proportion of added sugar to total energy intake (p > 0.05). LTOPA was only associated with some healthy eating behaviours, and there is much room for improvement in the diets of Swedish adolescents.

Diet diversity score and healthy eating index in relation to diet quality and socio-demographic factors: results from a cross-sectional national dietary survey of Swedish adolescents.

OBJECTIVE: Groups with low socio-economic status have less healthy diets and higher prevalence of non-communicable diseases. Using the latest Swedish national dietary survey data, we developed a healthy eating index and a diet diversity score with the aim to explore associations between the scores and socio-demographic factors. DESIGN: Cross-sectional national dietary survey. A web-based retrospective registration of food and beverages during 2 d was used to assess dietary intake. This information was used to construct the Swedish Healthy Eating Index for Adolescents 2015 (SHEIA15) and the Riksmaten Adolescents Diet Diversity Score (RADDS). The scores were based on the latest Swedish dietary guidelines from 2015. Intakes of food and nutrients across the scores were examined. Mixed-effects multilevel models were used to assess associations between the scores and household education, sex, school grade, weight status and school municipality. SETTING: School-based survey in Sweden. PARTICIPANTS: 2905 adolescents in grades 5, 8 and 11, 56 % girls. RESULTS: High scores on SHEIA15 and RADDS were associated with higher intake of vegetables, fish and several nutrients, and lower intake of sugar-sweetened beverages and red meat. Boys and participants in households with lower education level scored lower on both indices. Individuals with overweight/obesity scored lower on RADDS. CONCLUSIONS: The newly developed indices can be used to identify healthy eating patterns among Swedish adolescents. Both indices show that boys and adolescents from households with lower education level have poorer dietary habits. Lower diet diversity was related to overweight/obesity, but the overall healthy eating index was not.

Using different growth references to measure thinness and overweight among Swedish primary school children showed considerable variations.

AIM: The study compared how four different growth references determined the prevalence of thinness and overweight, based on height and weight measurements from a nationally representative sample of Swedish children from seven to nine years of age. METHODS: The height and weight measurements of 4518 Swedish schoolchildren aged seven to nine years were carried out in 2008 using a standardised protocol. The prevalence of different degrees of thinness and overweight was calculated using international growth references from the World Health Organization, the International Obesity Task Force and two Swedish growth references from Werner and Karlberg. RESULTS: Depending on which growth reference we used, the prevalence of different degrees of thinness varied from 7.5% to 16.9% for the boys and 6.9% to 13.7% for the girls, while the prevalence of overweight, including obesity and severe obesity, varied from 16.5% to 25.7% for the boys and 18.2 to 25.2% for the girls. There were also significant gender differences depending on the growth reference we used. CONCLUSION: Using four different growth references, two international and two Swedish, produced wide variations in the prevalence of thinness and overweight, together with significant gender differences. In the absence of a global definition, we need both national and international growth references.

Age and time effects on children's lifestyle and overweight in Sweden.

BACKGROUND: High physical activity, low sedentary behavior and low consumption of sugar-sweetened beverages can be markers of a healthy lifestyle. We aim to observe longitudinal changes and secular trends in these lifestyle variables as well as in the prevalence of overweight and obesity in 7-to-9-year-old schoolchildren related to gender and socioeconomic position. METHODS: Three cross-sectional surveys were carried out on schoolchildren in grades 1 and 2 (7-to-9-year-olds) in 2008 (n = 833), 2010 (n = 1085), and 2013 (n = 1135). Information on children's level of physical activity, sedentary behavior, diet, and parent's education level was collected through parental questionnaires. Children's height and weight were also measured. Longitudinal measurements were carried out on a subsample (n = 678) which was included both in 2008 (7-to-9-year-olds) and 2010 (9-to-11-year-olds). BMI was used to classify children into overweight (including obese) and obese based on the International Obesity Task Force reference. Questionnaire reported maternal education level was used as a proxy for socioeconomic position (SEP). RESULTS: Longitudinally, consumption of sugar-sweetened beverages ≥ 4 days/week increased from 7% to 16% in children with low SEP. Overall, sedentary behavior > 4 hours/day doubled from 14% to 31% (p < 0.001) and sport participation ≥ 3 days/week increased from 17% to 37% (p < 0.001). No longitudinal changes in overweight or obesity were detected. In the repeated cross-sectional observations sedentary behavior increased (p = 0.001) both in high and low SEP groups, and overweight increased from 13.8% to 20.9% in girls (p < 0.05). Overall, children with high SEP were less-often overweight (p < 0.001) and more physically active (p < 0.001) than children with low SEP. CONCLUSIONS: Children's lifestyles changed longitudinally in a relatively short period of two years. Secular trends were also observed, indicating that 7-9-year-olds could be susceptible to actions that promote a healthy lifestyle. Socioeconomic differences were consistent and even increasing when it came to sugar-sweetened beverage consumption. Decreasing the socioeconomic gap in weight status and related lifestyle variables should be prioritized. Primary school is an arena where most children could be reached and where their lifestyle could be influenced by health promoting activities.

Stable prevalence of obesity in Swedish schoolchildren from 2008 to 2013 but widening socio-economic gap in girls.

AIM: The aim of this study was to follow the 5-year prevalence of overweight, obesity and thinness in 7- to 9-year-old children in West Sweden and to investigate whether trends differed according to gender and socio-economic status. METHODS: Cross-sectional anthropometric measurements of three cohorts in grades one and two were performed in 3492 7- to 9-year-old children in 2008, 2010 and 2013. For body mass index classification, the IOTF/Cole and WHO 2007 references were used. Percentage of inhabitants with high education in the school area was used for socio-economic classification. RESULTS: Between 2008, 2010 and 2013, the overall time-trends in overweight 17.7%, 19.3% and 18.8%, obesity 3.2%, 3.3% and 3.1%, and thinness 6.5%, 4.7% and 6.9%, respectively, were fairly stable using the IOTF/Cole references. Thinness defined by the Cole reference increased in girls. The socio-economic gradient for overweight and obesity was clear by both references, but using the IOTF reference, the gap increased for obesity among girls (p = 0.024). No significant trends were observed with the WHO reference. CONCLUSION: The overall prevalence of overweight and obesity was stable over 5 years, but we detected growing inequality in obesity and increasing prevalence of thinness in girls. With these regionally representative data, we can draw conclusions about West Sweden, despite an absence of continued national surveillance.

Design, Methods, and Participation in Riksmaten Young Children-A Swedish National Dietary Survey.

Background: National dietary surveys provide essential data for risk benefit assessments of foods and nutrients, for management and policy development. Physical activity measurement and biomonitoring can provide important complementary data but are less commonly included. Objectives: This study aimed to describe the study design and methods of the cross-sectional Swedish national dietary survey Riksmaten Young Children (Riksmaten småbarn), of children aged 9 mo, 18 mo, and 4 y. Participation/dropout rates for the 2 older age groups are also presented. The impact of different recruitment strategies is discussed. Methods: Children (N = 16,655) were randomly selected from the population register; invitations to guardians were sent by post and where possible, followed up by telephone. Food intake was assessed by a 2-d food diary and/or questionnaire. Height and weight were reported after measurement. Physical activity (accelerometery, 7 d) and stool, blood, and urine samples were assessed in subgroups. Results: Food consumption data were collected in 1828 children (11% of the invited; 18 mo: n = 1078, and 4 y: n = 750). Of participants also in subgroups, 71% provided physical activity data (n = 1307), 60% stool samples (n = 630), and 51% blood and/or urine samples (n = 593). The study population represented all geographic regions and types of municipalities in Sweden, but participating households had both higher education level and higher income than the target population. Only minor differences were seen in participation rates between recruitment via post and telephone compared with those through post only (12% compared with 10%). Repeated contact attempts were needed for the majority of participants (65%). Despite the low-participation rate, 99% of the participants completed the study once started. Conclusions: Although it was a challenge to recruit participants, Riksmaten Young Children provides a substantial amount of information at national level, representative in terms of sex, geography, and family structure. The underrepresentation of households with lower socioeconomic position must be considered when generalizing results.

Dietary Greenhouse Gas Emissions and Diet Quality in a Cross-Sectional Study of Swedish Adolescents.

BACKGROUND: Interventions to improve dietary intake and reduce dietary greenhouse gas emissions (dGHGE) are urgently needed. Adolescence presents a unique time in life to promote sustainable diets. Detailed dietary data are needed to inform public health strategies aiming at improving adolescents' diet quality and reducing dGHGE. OBJECTIVE: This study aimed to describe dGHGE in Swedish adolescents' diets by socio-demographic characteristics, evaluate how food groups contribute to dGHGE, and examine dGHGE in relation to diet quality. METHODS: Data come from the national, school-based, cross-sectional dietary survey Riksmaten Adolescents 2016-17 of 3099 females and males attending school grades 5 (11-12 y old), 8 (14-15 y old) and 11 (17-18 y old). Participants completed 2 web-based 24-h recalls and questionnaires on lifestyle factors. dGHGE was estimated based on life cycle assessment data. Diet quality was estimated using NRF11.3 (Nutrient Rich Food Index) and SHEIA15 (Swedish Healthy Eating Index for Adolescents 2015). RESULTS: dGHGE were higher in males than females (medians 4.2 versus 3.8 kg CO2e/10 MJ, P < 0.001). In females, dGHGE were highest in grade 5 (4.0 kg CO2e/10MJ), whereas in males, emissions were highest in grade 11 (4.4 kg CO2e/10MJ), P < 0.001 for the sex/grade interaction. Overweight/obesity was positively associated with CO2e/10MJ, but parental education, birthplace, and degree of urbanization were not. In females, the proportion of dGHGE from animal-based foods was lowest in grade 11, whereas the proportions from plant-based foods and sweet foods/beverages were highest. In males, these proportions were similar across grades. NRF11.3 was not associated with CO2e/10MJ, whereas healthier eating, according to SHEIA15, was inversely associated with CO2e/10MJ. CONCLUSIONS: Food choices and dGHGE per calorie differ by sex in adolescents. Thus, intervention strategies to improve dietary sustainability need to be tailored differently to females and males. Diet quality should also be considered when promoting reduced GHGE diets.

The Contribution of Foods and Beverages of Low Nutritional Value to the Diets of Swedish Adolescents, by Food Group, Time and Place. A Nationally Representative Study.

Adolescence is a time in life when lifestyle behaviours are acquired. One indicator of poor diet quality is the intake of foods and beverages with a relatively low nutritional value. Using the Australian classification of such foods, termed "discretionary", we classified the intakes of Swedish adolescents who participated in the Riksmaten Adolescent 2016-17 national dietary survey. From selected schools, 3099 adolescents in age groups 11-12, 14-15 and 17-18 years provided two 24-h recalls. Intakes and healthy dietary scores were calculated. Plasma ferritin, folate and 25(OH)D were available for a third. Almost 40% of total energy came from discretionary foods/beverages. Adolescents with higher intakes were more likely to be female, older, from a low socioeconomic position-household and born in Sweden. Most discretionary foods/beverages were consumed on weekend days and during in-between meals, outside of the home and at school. Percent energy from discretionary intake was associated with healthy dietary scores but not nutritional status. A substantial amount of energy was obtained from discretionary foods/beverages, and we found that consumption is pervasive across sociodemographic factors, time and place. Addressing this pattern will require a comprehensive approach to food environments and behaviours to reach all adolescents in an equitable manner.

Mycotoxins in blood and urine of Swedish adolescents-possible associations to food intake and other background characteristics.

The exposure to mycotoxins of Swedish adolescents is currently unknown. The aim of the present study was to investigate the exposure to mycotoxins and their association with food intake, and background characteristics in adolescents of a national dietary survey. About 3000 school students (1000 from the 5th, 8th and 11th school years) were recruited for the survey. The participants completed Web-based questionnaires on food propensity, sociodemography and health, and a Web-based dietary recall. Spot urine and blood samples were collected from 1105 of the participants for mycotoxin biomarker analysis. Mycotoxins were analysed with multibiomarker methods in urine (HPLC-MS/MS) and serum (HPLC-MS/MS). Of the 35 different analytes in urine, the frequency of positive samples were the following: deoxynivalenol (DON, 4.8%), DON-15-ß-D-O-glucuronide (DON-15GlcA, 9.1%), dihydro-citrinone (DH-CIT, 0.5%), HT-2-glucuronide (HT-2-3-GlcA, 0.1%) and ochratoxin A (OTA, 0.1%). Of the 27 different analytes in serum, OTA was detected in all samples, while 2'R-ochratoxin A (2'R-OTA) was found in 8.3% and enniatin B (EnB) in 99.2% of the samples. Exposure assessment calculations were performed on OTA from the serum concentration and on DON equivalents (DON eqv) from the urine concentration. All probable daily intake (PDI) estimates were below tolerable daily intakes, except for 1.6% of the participants for DON. The maximum PDI was 4.3 µg DON eqv/kg body weight and day. Consumption of cereal grain commodities was associated with levels of DON, EnB or OTA in biofluids. Serum OTA was also associated with intakes of raisins and coffee. Furthermore, coffee consumption correlated well with 2'R-OTA concentration in serum. In conclusion, exposure to mycotoxins in Swedish adolescents is common, but fortunately, high exposure was rare.

Procedure to Estimate Added and Free Sugars in Food Items from the Swedish Food Composition Database Used in the National Dietary Survey Riksmaten Adolescents 2016-17.

A high intake of added and free sugars is associated with poor diet quality, caries, and potentially has a role in non-communicable diseases. As a result, dietary guidelines advice limitation. However, there is no standardized method for estimation of added and free sugars in food items and consequently intake is difficult to measure. This study aimed to refine a procedure for sugars estimation and apply it to a Swedish dietary survey on adolescents (Riksmaten Adolescents 2016-17). A national sample of 3099 adolescents in school year 5, 8 and 11 participated (55% girls). Individual dietary intake data from two non-consecutive days was collected retrospectively and used for analysis. A ten-step systematic procedure for estimation of sugars in a Swedish context has been developed by combining two earlier methods, one for estimation of added sugars and one for free sugars. Sugars estimates were made for all food items comprising the survey database. Mainly objective decisions were necessary to make the estimates (92% and 93% for the sugars respectively); meaning that the procedure was largely transparent. In relation to Nordic Nutrition Recommendations, 45% of the participants had an intake that adhered to the guidelines. However, the majority of intakes was close to the recommendation. Further research on how specific food sources contribute to added and free sugars is necessary to facilitate further guidance on sugars and how to reach recommended target levels in Sweden.

Riksmaten Adolescents 2016-17: A national dietary survey in Sweden - design, methods, and participation.

BACKGROUND: Nationally representative information on food consumption data is essential to evaluate dietary habits, inform policy-making and nutritional guidelines, as well as forming a basis for risk assessment and identification of risk groups. OBJECTIVE: To describe the methods used in the Swedish national dietary survey of adolescents, Riksmaten Adolescents 2016-2017. DESIGN: Students in grades 5, 8, and 11 (mean ages 12, 15, and 18 years) were recruited in this school-based cross-sectional survey. A new, validated, web-based method was used to assess dietary intake. Information on physical activity, health, and socioeconomic background was collected through web questionnaires. Physical activity was also evaluated by accelerometers. Weight and height were measured in all participants, while blood and urine samples were collected in a subsample of 40% of the participants. RESULTS: A total of 3,477 (68%) respondents participated and 3,099 (60%) had complete dietary information. In the subsample, 1,305 (55%) respondents participated and 1,105 (46%) had complete dietary information. The participants were overall representative for the population with regard to socioeconomic background and school organization (public or independent). All types of municipalities were represented in the survey and overall, the geographic distribution corresponded to the underlying population. Some differences by school grade were observed. Sample weights were calculated for the total sample and the subsample. CONCLUSION: The Riksmaten Adolescents 2016-2017 provides valuable national data on diet, physical activity, and markers of exposure in age groups where data have been lacking. The data will provide a valuable basis for risk assessment, public health policy, and in-depth analyses.

Heme iron-based dietary intervention for improvement of iron status in young women.

OBJECTIVE: Conventional iron deficiency treatment with pharmacologic iron doses often causes side effects. Heme iron has high bioavailability and a low capacity to cause gastrointestinal side effects. This study investigated the possibility of using heme iron in the form of blood-based crisp bread as a diet-based treatment program to improve the iron status of women of reproductive age. METHODS: In a 12-wk intervention study, 77 women (mean age 24 y) were assigned to one of four groups: blood-based crisp bread (35 mg of iron [Fe], 27 mg of which was heme Fe), iron supplementation consisting of 35 mg of non-heme iron/day (Fe35), iron supplementation consisting of 60 mg of non-heme iron/day (Fe60), and controls (iron-free tablets). RESULTS: Body iron increased significantly in the crisp bread group by a median of 2.7 mg/kg (interquartile range 3.1, n = 18), in the Fe35 group by 2.7 mg/kg (interquartile range 2.8, n = 11), and in the Fe60 group by 4.1 mg/kg (interquartile range 3.6, n = 13), whereas no change was observed in the control group. No statistically significant difference in iron status increase was observed between the crisp bread group compared with the two iron-supplemented groups. CONCLUSION: Dietary-based treatment containing heme iron has few side effects and can be used efficiently to improve the iron status of women of reproductive age.